1. Field of the Invention
The embodiments of the present invention relate generally to inkjet printing mechanisms, and in particular to squeegees for wiping excess ink off inkjet printheads.
2. Background of the Invention
Inkjet printheads eject controlled sprays of ink onto a page while printing. Each such printhead has very small nozzles through which drops of various colored ink are fired. To print a typical image, the printhead is moved back and forth across a page, while ejecting patterns of ink drops. Conventional printheads use piezo-electric and thermal printhead technology. For instance, thermal ink ejection mechanisms are shown in U.S. Pat. No. 5,278,584 issued to Brian J. Keefe et al on Jan. 11, 1994 and U.S. Pat. No. 4,683,481, issued to Samuel A. Johnson on Jul. 28, 1987.
A wiper assembly mechanism is typically mounted within the housing of the printing mechanism to clean and protect the printhead. The printhead can be moved over the assembly for maintenance, specifically for wiping off ink residues and any paper dust or other debris that have collected on the printhead.
A wiping sequence generally includes a forward and a backward wiping stroke. In the forward stroke, a wiper blade of the wiper assembly moves from its home position and across the printhead to scrape off ink residues from the printhead. After the forward stroke, the wiper blade moves back to its home position in the backward stroke and wipes the printhead a second time.
In the forward stroke, most ink residues on the printhead are wiped off, and such wets one side of the wiper blade. On the backward stroke, a dry wiping of the printhead occurs if no other fluids are used to moisten the wiper blade. Dry wiping of the printhead can damage the nozzles on the printhead and the wiper blade itself. What is needed is a squeegee and method that reduce or prevent such printhead wear and damage.